Ecology Flashcards
What is ecology
The study of an organisms environment and the factors that determine their distribution and abundance in that environment
Ecosystem
A unit containing all of the organisms and their environment, interacting together in a given area
Habitat
The place where an organism lives
Population
A group of organisms of the same species living in a habitat
Community
All the populations of the different species living in a habitat
Producer (autotrophs)
An organism that makes its own organic nutrients, usually using energy from sunlight
Consumer (heterotrophs)
An organism that gets its energy by feeding on other organisms
Decomposed (heterotrophs)
An organism that gets its energy from dead or waste organic matter
Food chain
A chart showing the flow of energy from one organism to the next beginning with a producer
Tropic levels
The position of an organism in a good chain or food web or the number of energy transfers from the energy sources
Food web
A network of interconnected food chains showing the energy flow through part of an ecosystem
Tropic level 1
Producer
Tropic level 2
Herbivore (primary consumer)
Tropic level 3
Carnivore (secondary consumers)
Tropic level 4
Carnivore (tertiary consumers)
What are quadrants used in?
Sampling plants - they mark off the exact area so that the plants in that area can be identified and counted
What are quadrants made of?
Metal, wood plastic
Using a quadrat:
1) grid area for sampling
2) quadrat should be placed randomly within the grid
3) count number of organisms inside the quadrat
4) use several quadrat samples
5) use sample to calculate numbers in total areas
What do you do for motile organisms with quadrats?
Aerial sampling
Counting from an aircraft
Multiplying the average number counted in the quadrats by the total area
How to make using quadrats more reliable for motile organisms
Repeat sampling over a number of years
Under similar conditions
Same time of year
Allow for animals not seen
Name 3 ways which ecosystem’s interact with each other
Feeding amount organism s
Competition
Interactions between organisms and the environment
Biotic Factors - which influence the numbers and distribution of organisms in an ecosystem
Availability of food + competition for food resources Parasitism Predation Disease Presence of pollinating insects Availability of nest sites
Abiotic factors
Climate (light intensity, water availability)
Hours of daylight
Salinity (salt content)
Pollution
Soil conditions (clay no tent, nitrate level, particle size, water content, pH)
What is biodiversity?
The term refers to the variety of life on earth at all its levels, from genes to ecosystems
Order of levels
Producer - primary consumer - secondary - top carnivore
What do pyramids of numbers do?
Visualises/ explains the numbers in the food chain/web
What happens to the energy as you go up the levels in a pyramid of numbers?
Energy is lost to the surroundings
What is biomass
Biomass is the total dry mass of one animal/plant species
Pyramids of biomass - bars get narrower towards the top
Why is it difficult to get valid data for a pyramid of biomass
- measuring dry biomass means that all the water has to be removed
- an organism Amy belong to more than one tropic level, so it cannot easily be represented by one bar
Pyramids of energy
Energy decreases going up
Based on per year/ per area
Example :
When a rabbit eats grass, not all of the materials in the grass end up as rabbit, why are there losses
Some parts of the grass aren’t eaten
Some parts are not digested and so are not absorbed
Some of the materials absorbed form excretory products
Many of the materials are repaired to realise energy with the loss of CO2 and water
Why is only 10% of energy transferred from one trophic level to the next
90% is lost through heat, undigested material, respiration to release energy for life processes, not eaten food, excretion
Give one way of transferring energy between organisms
Feeding
Give the process of flow of energy through ecosystems
1) photosynthesis fixes sunlight energy into chemicals (glucose)
2) respiration releases energy from organic compounds
3) if energy released is used to make new cells, then energy remains fixed in molecules
4) if energy released is used for other processes - escape as heat
Which molecules contain carbon?
Carbohydrates, lipids, proteins, DNA
Name the 5 important processes in cycling carbon
Photosynthesis Feeding and assimilation Respiration Fossilisation Combustion
What does feeding and assimilation do in cycling carbon
Pass carbon atoms already in organic compounds along food chains
What does respiration do in cycling carbon
Produces inroganic CO from organic compounds as they are broken down to release energy
What does photosynthesis do in cycling carbon
Fixes carbon atoms from CO2 into organic compounds
What is nitrogen present in
Proteins, amino acids, most vitamins and DNA
Name the key processes in this cycle
Feeding and assimilation
Decomposition
Nitrification
What does decomposition do in the nitrogen cycle
Decomposition by fungi and bacteria produces ammonia from the nitrogen in compounds like proteins and DNA
What does denitrifying bacteria do
Use nitrates as an energy source and convert them into nitrogen gas - reduces the amount of nitrate in the soil
What do nitrogen fixing bacteria in root nodules do
Make ammonia, this is converted by the plant into amino acids
What is produced when fossil fuels burn
Selfie dioxide and carbon monoxide
What is CO
Carbon monoxide
- Colourless, odourless and tasteless
- Passes into red blood cells after breaking it in
- binds more strongly to haemoglobin than oxygen does
What is SO2
Sulfur dioxide
- sharp, choking smells
- when sulfur dioxide dissolved in water droplets in clouds it causes acid rain
What does acid rain do
Damages waxy layer of tree leaves
Makes it more difficult for trees to absorb minerals
What does the acidification of lakes do
Causes death of bacteria and algae; death of fish and amphibian eggs; change in ecosystems)
What does acidification of soil do?
Leaching of some ions in lakes, kills fish, root hairs less effective at absorbing minerals so tree growth is slowed)
What are the natural causes of air pollution
Volcanic eruptions and lightning
Water vapour from clouds
Rain
What are the human causes of air pollution
Burning fossil fuels
List the key greenhouse gases
Water vapour, CO2, nitrous oxide, methane, CFCs
Why is there more CO2 in the atmosphere
Increased combustion of fossil fuels
Increased deforestation
Name a few of the consequences of global warming
Melting polar ice caps - sea level es would rise
Change in the major ocean currents - warmer waters flow into previously cooler areas
Change in global rainfall patterns - could result with a rise in temp
What happens if there is a rise in temperature
More evaporation from surface of the sea
More water vapour in atmosphere
Long term climate change
What causes water pollution
The discharge of harmful substances into rivers, lakes and seas
What happens if untreated sewage gets into rivers
Microorganisms decompose it, this means that due to the oxygen from the water usually being used for aerobic respiration, there is less oxygen dissolved in water
Fish and other aquatic creatures will die
What is the sequence of events do eutrophication
Increase in mineral ions Algal bloom Death of algae Decomposition by aerobic bacteria Bacteria use up oxygen Fish die and
Where do excess mineral come from
Sewage and artificial nitrate/phosphate fertiliser
What are the problems with fertilisers
When they are washed off the land by rainwater into rivers - leaching
Causes an increase in the levels of minerals
What is the full process of eutrophication
Sewage/fertiliser run off increases the nutrient concentration of the water
Extra nutrients cause increased growth of algae
Algal bloom covers the waters surface killing any plants below surface
Algae also die as nutrients run out
Aerobic respiration decompose the dead plants
Bacteria use up oxygen for respiration
Fish die from lack of oxygen
What happens if their is reduced soil quality
No trees/plants to return minerals to the soil when they die
Crops planted in deforested areas rapidly use up minerals from soil
What happens if erosion occurs
Soil is exposed due to lack of tree cover
Soil washed into rivers - rising water levels and flooding lowland areas
What is global warming
Increase in the mean temperature of the earth
What is a greenhouse gas
A gas that absorbs infrared radiation from the sun
Nitrous oxides
Released from fertilise production
Released in treatment of domestic waste water
Methane
From rice paddy fields
Cattle farming
CFCs
Aerosol sprays
